The activation of Insulin Like Growth Factor-1 (Igf-1) to its receptor (Igf-1r) plays an important role in the process of adipogenesis. The inhibition of Igf-1 and its receptor at the early process is the precise step for the therapy of obesity. This study used obese rats treated with ellagic acid and Rambutan Peel Extract (RPE) 30mg/kgbw dose. The Igf-1 and Igf-1r expression in visceral fat tissue was observed using immunofluorescence double staining, which confirmed later by western blotting. The results reveal that the use of RPE30mg/kg BW on obese rats model can provide inhibitory effect on the expression of igf-1 and igf-1r as in a normal rat. The expression of igf-1 and its receptor highest in obese rats and the lowest expression in obese rats which were treated with ellagic acid. The reduced expression of igf-1 and its receptor will reduce ERK1/2 and PPAR expression in adipogenesis signaling cascade and in turn inhibits adipogenesis.

Keywords: Igf-1, Igf-1r, Rambutan Peel Extract (RPE)

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